Process of making substitutes for horn and ivory from viscose



Patented Dec. 13, 1927.

UNITED STATES PATENT OFF-ICE...

HANS noennr, or wonrnnsnonr, Irma ERKNER, GERMANY),

raoonss or MAKING suns'rrru'rns non norm Am) IVORY mom vIseosE,

' No Drawing. Application filed March 26, 1924, Serial No. 702,130, and in Germany December 29, 1922.

It is well known that viscose (sodiumcellulose xanthogenate solution), eoagulates on long standing and heating i. e. it is converted into an insoluble substance.

substance thus obtained has been freed from alkali metal hydroxide and alkali metal sulphides by long washing and by drying, a

horny substance is obtained which may be used for various useful articles. It iskn-own 1 as viscoid and may be used as a substitute for horn or vegetable ivory (or stone nut substitute).

the manufacture of viseoid is the washing process. It is. extremely difficult t0 Ie I10Ve by lixiviation the alkali metal hydroxide and alkali metal sulphide, especially from washing. Owing to the extended -lixiviation, the

substance undergoes alteration in consequence of which even after drying it is 111- clined to suffer a change--in condition or form. Even in dry condition when stored integrates by cracking or crumbling.

My invention is based on the discovery .that theiabove mentioned defects may be overcome by treating the crude or prelimi- 3 narily purified sodium cellulose xanthogen ate solutions with heavymetal salts or alka-- line earth compounds. For this treatment such salts are selected which readily give off their inorganic or organic acid radicals to the alkali (sodium hydroxide or sodium sulphide). Such metallic oxides and metallic hydroxides as form compounds with alkali metal hydroxids and alkali metal sulphides,-

(for example aluminum or zinc hydroxides) may also be employed with a good-result. The reaction'must be carried out slowly and gradually by a correct selection and regulation of the temperature during the-treatment, in order that theviscose may not be r prematurely converted intoan insoluble condition, i. e. before it is introduced into the moulds.

For many useful articles, the product thus obtained by the above process-before final washing. with water may be subjected to treatment with substances which fix the heavy metals or alkali earth metals for instance by treating the "sodium aluminate formed with calcium chloride, whereby in- When the.

large pieces which require at least days it exhibits little durability as it slowly diseasily removed by washing.

Elm-ample] 100 kilograms crude or preliminarily'purified viscose (containing about 7 kilograms alkali) are before coagulation thoroughly agitated in a kneading machine with an excess of about lti kilograms dry) of. aluminum hydroxide under con- I tinuous cooling to 15- degrees centigrade (if The'mo'st (lilfilclllt operation to carry out 111 \Vhen coagulation has taken place a shortwashing for about 5 days-will-sufliee. 'In

i fixing the aluminum in the. mass it 1s treated, before being washed-for example with a saturated solution of calcium chloride solution, with or Without heating, then thoroughly washed and finally dried Example [1.

7 kilograms (calculated dry) freshly prel caiculated when cipitated ironoxide isslowlykneade'd 'or agitated for about two'hours in 100. kilograms crude or preliminarily purified viseoseand then when reaction has taken place (which can, be easily ascertained from the dark color) about 9 kilograms of'zinc oxide are. added in small portions and-thoroughly agitated in vacuo. Reaction temperature 1s 10 degrees centigrade, After coagulation in moulds it is washed for about 3-4 days and then dried.

E sample I I l About 17 kilograms ofcalcium acetate is kneaded or agitated in small portions (in vacuo) in kilograms of crude or preliminarily purified viscose and well cooled to- +5 degrees centigrade. After about .two

hours mixing the mass is cast in moulds and left to harden. After coagulation the mass is washed in running water for about three days and then dried.

Coagulation is rather-a pol rnerization of cellulose xanthogenie acid xanthogenate) molecule with the separation out of the sodium as sodium sulfidor in some'other form.

This invention is vnot predicated upon a process for forming heavy metal compounds.

with a viscose but rather upon a process in which'the heavy metal compounds are employed to combine with the accompanying products which are free in the viscose and which exert an injurious influence on'thei Washing process and thereby on the entirev substance.

I claim: 1. [he process for the manufacture of a horn or vegetable ivory substitute which comprises treating freshly prepared viscose i "with aluminum hydroxide to combine with hydroxid to the alkali metal hydro-xide and sulphide present and then treating the mixture with 1 a solution of calcium chlorid.

2. The procgs s for the manufacture of a horn or vegetable ivory substitute which comprises treating viscose beforecoagulation with aluminum hydroxid to combine with the'alkali metal hydroxide and -'sul-. phide present and at the same time 'main-' taming-a temperature of approximatelylli'i with the alkali metal hydroxide and sulphide present and at-the same time maintam ng a temperature ofapproximately 15 degrees centlgrade fixing the aluminum in the .mass by adding a solution of calcium chlorid and then washing the final product. .4. The processfor the manufacture of a horn or vegetable ivory substitute which --comprises thoroughly agitating 100 kilograms of sodium cellulose xanthate with approximately 16 kilograms of aluminum combine with the alkali-metal hydroxide and sulphide present and at the same time cooling the mixture to approximately 15 degrees. centigrade, permitting the mass to coagulate and harden and then fixing the aluminum in the mass With a saturated solution of calcium chlorid then washing the mass.

- 5. The process for the manufacture of a horn or vegetable ivory substitute which comprises treating freshly prepared viscose with a heavy metal compound having amphoteric qualities which is soluble in the viscose to coinbine with free alkali metal hydroxid and alkali metal sulphide present in the viscose and thcn-eonverting the heavy metal salt into an insoluble one for fixing said heavy metal in the viscose by the use of calcium chloride. I

6. The process for the manufacture of a horn or vegetable ivory substitute which comprises treating freshly prepared viscose with a heavy metal compound which is soluble in the viscose/to combine with free alkali metal hydroxid and alkali metal sulphide present in the viscoseat the same time maintaining the mass at approximately 15 degrees and then converting the heavy metal salt into 'an insoluble one for fixing said heavy metal. in the viscose by the use of calcium chloride.

7. The process for the manufacture of a horn or vegetable ivory substitute which 1 comprises treating freshly prepared viscose with a heavy metalcompound which issoluble inthe viscose to combine with free alkali metal hydroxid and alkali metal sulphide present in the viscose at the same time maintaining the mass at approximately 15 degrees, removing air from the cooled mass, and then converting the heavy metal salt into an insoluble one for fixing said heavy metal inthe viscose bythe use of calcium chloride.

In testimony whereof I have signed my name to this specification.

' HANS EGGERT. 

